'Time Scanners' aims technology and an eye for forensics at the world's iconic structures

Using laser technology, the new series uncovered architectural secrets that pushed some researchers to rewrite their dissertations.

From the new series "Time Scanners," a highly accurate laser scanned rendering of the Great Pyramid in Egypt. (Image: Atlantic Productions)

Like X-rays that reveal the bones and organs of the human body, portable laser technology has made it possible to analyze man-made structures, mapping their interiors to see how they were built. In the three-part PBS series "Time Scanners," this cutting-edge tech is put to use to reveal the inner workings of the Great Pyramid in Egypt, St. Paul's Cathedral in London, and the ruins at Petra, Jordan. In the July 1 premiere, engineer Steve Burrows starts with the earlier, lesser-known Step Pyramid, Collapsed Pyramid and Bent Pyramid to the chart architectural evolution that resulted in the Great Pyramid at Giza. He shared his insights with MNN.

MNN: How did the series come about?

Steve Burrows: Atlantic Productions approached me, as I have done TV work for them before, notably "Engineering the Impossible," and "Unearthing Ancient Secrets." They outlined the idea for the show to me and asked if I was interested. What engineer on the planet wouldn't want to do this? So of course I said yes immediately.

How did you decide which structures to include?

The location list varied and originally included Angkor Wat, and potentially the Great Wall of China, but the limitations on location were mostly access permits and cost. The six places chosen included five in easy reach of London, where Atlantic Productions are based, plus Machu Picchu. The difficulties of Peru showed that on long-haul locations, the additional factor of time becomes an issue, and I am sure that was the most expensive episode to film. However, Machu Picchu proved that remote locations are not a barrier to the technology, and that the formula for the show knows no geographic boundaries.

How long has this portable laser technology existed? How long have you been working with it?

Lasers in construction have been around for quite a while, but the availability of the mobile laser scanner is quite recent, as is the technology to create point clouds and transfer that data cheaply and easily. So it is, in fact, the perfect storm of technology in both the instruments and data capture and transmission that creates the breakthrough. I was quite new to the technology, and the great thing for me was that once I stopped thinking of the point cloud as an image, and started thinking of it as raw data, the opportunities to post-process that data by using it as input to other software opened my eyes to the true potential. Once I thought that, then anything became possible. Also, you can pair this technology with older technologies, as we did. We used ground-penetrating radar (GPR) with laser scanning, which is like pairing a snail with a Ferrari, and proved that the combination is powerful. The trick here is to use the lasers to enhance older technologies, so I could well imagine photogrammetry or even a tape measure, plumb bob or string line, being paired with lasers to discover new things.

Does it have limitations? Explain what it does and how it works.

Yes, it has physical limitations regarding size, temperatures and the need for mobile power. But these are not very restrictive as the scanners are small, and work at 120 degrees Fahrenheit and I'm told very cold temperatures, too. The next limitations are the data transfer speeds, but transferring cloud to cloud seemed pretty fast, too. The equipment is pretty amazing and could be flown on opticopters, helicopters and light aircraft to scan from the air and can easily be carried in a rucksack to scan from the ground. It works by simply bouncing a beam of light — a laser beam — off an object and measuring the distance from the scanner to the object. That might sound simple enough but imagine then moving the scanner, and having the ability to take literally millions of measurements from different places that then are stitched together into one model. The points are so close that you see everything. It's like painting by using dots, and when you get millions of them its like a 3-D TV set but all the points are real data, so you can manipulate it. The data needs some post processing to link up the scans, and to do that there are targets set and you simply align the targets to join the scans, much like you put wallpaper on the wall, except digitally. The whole process is intuitive and simple which means that mistakes are easy to avoid.

How accurate is it?

Accuracy simply depends on how many points you scan and how far away you are. The further away, the lower the resolution and the more points than the higher the density. But you can see pretty well anything you can see with your eye. It’s as good as we are at seeing the things you scan, but unlike us, the data is stored in a memory that can be retrieved perfectly.

For each of the episodes, what was the approach going in?

It varied from place to place, but basically the idea was that I took a look around and tried to place myself in the position of the client's engineer. So if I was asked to design and build these things, how would I do it? I took the view that the human brain hasn't evolved too much in the last 6,000 years so perhaps the logic would be the same. Using that as my guide, I used the technology to explore my theories and see if I could prove that they thought like us. For example, in Machu Picchu, the slopes are steep and the terracing looked different to my eye, so by using a combination of ground-penetrating radar with laser scanners, I was able to prove my theory that they used basic engineering physics to solve three different problems of growing food, stabilizing slopes and keeping the terracing from falling off the mountainside. In other places the problems were different. For example, in Petra, I wondered how 10,000 people were fed and watered daily in the desert, and using the lasers we discovered how irrigated fields were created by damming a small stream and wetting the ground, much like the latest craze of dry farming that we have in California today. This is where learning from the past can guide us in the future and it's amazing to re-discover it.

A laser scan of the ruins of Petra show a staircase in front of the famous structure that would likely have aided in construction (Image: Atlantic Productions)

What expectations did you have? What were the biggest surprises you found?

I didn't know how the show would pan out, so I didn't have any great expectations, to paraphrase Charles Dickens. However, the surprises were many. I found out that the Romans were great fire engineers, that Herod the Great was an amazing civil engineer and construction scheduler, that the Incas sized Machu Picchu to suit the availability of water, which we were able to measure, that the Egyptians passed on learning for 100 years, that the Nabitheans considered construction safety and that Christopher Wren was a master of structural disguise. These and many more discoveries were down to the combination of technology, engineering and archaeology and I think that we are learning every day that it's at the intersections of the sciences that discoveries are being made.

For the Egypt episode, why not scan the other two pyramids at Giza as well?

We scanned the Great Pyramid but others were not scanned simply due to time constraints. What you see in the show is us scanning a pyramid a day for four days plus one day processing and analyzing. Imagine the pace and hours we worked to do that. Human need for sleep was the limiting factor, especially in my case!

What were your biggest challenges for each structure?

The challenges were consistently lack of time. As with designing and building in real life, the quality improves with time and we simply didn't have enough time. However, the locations themselves were challenging, and we filmed so much more than is in the show; it took over six months to edit the programs because of the huge amount of really good content. The temperatures were a challenge, 120 degrees Fahrenheit in Egypt, carrying the scanners to 10,000 feet up a mountain in Peru certainly challenged my fitness, and in London the challenge was tourists. So it wasn't a technology challenge, it was much more a human one.

What is the historical significance of the findings?

I am an engineer, not an archaeologist, but I worked in each case with an archaeologist, and the squeals of delight, comments about rewriting their Ph.Ds, new theories and general awe about our findings, told me that we were indeed breaking new ground. I simply did the science and engineering piece and let them tell me what they thought, and the outcome was amazing. I have done TV before and never had this reaction and so that made me excited about what we were doing.

Firstly, I hope I encourage some people to become engineers. I get fan mail from around the world, and people have told me that I have inspired them to become engineers, and that’s a huge personal satisfaction and even better if one day they come to WSP. I also hope people will see places they want to visit and learn more about because when I was at school I didn't consider history important but I now feel that learning from the past is important to understand what works and what doesn't, and the world is an amazing place. Having the series air here in the U.S. on PBS paired with another historical mystery show is a great opportunity to bring the past to life. PBS has long been known as the home of this type of content, so this is a great venue for bringing this content to larger audiences. With a mission to "promote human knowledge," PBS and WSP have the same basic purpose: education. My horizons are broadened, and I think I am wiser for that experience. I also want the data to be open sourced and free to be used by others so that this one show inspires life long learning about these places and the people who created them. I love that the data will live on. Finally, I hope it's entertaining, and that people see how much fun I had.

If there are more episodes, what other structures do you want to scan?

Everyone asks me that, and the sky is literally the limit. My choice would be to uncover El Mirador, the world's largest pyramid, to show the Great Wall of China in all its full glory and to bring to life the greatest civilizations on earth through their engineering. However, we could scan modern structures, the Burj Khalifa, Empire State Building, or maybe the Eiffel Tower. Anything is possible and so the series could run forever and maybe have more episodes than "The Simpsons" eventually. Yes, that's my aim, to have more shows on air than Bart Simpson. I might just make that my epitaph!